Revisiting the acoustics of speaker gender perception: A gender expansive perspective

Word and Gender Identification in the Speech of Transgender Individuals

Listeners use speech to identify both linguistic information, such as the word being produced, and indexical attributes, such as the gender of the speaker. Previous research has shown that these two aspects of speech perception are interrelated. It is important to understand this relationship in the context of gender-affirming voice training (GAVT), where changes in speech production as part of a speaker's gender-affirming care could potentially influence listeners' recognition of the intended utterance. This study conducted a secondary analysis of data from an experiment in which trans women matched shifted targets for the second formant frequency using visual-acoustic biofeedback. Utterances were synthetically altered to feature a gender-ambiguous fundamental frequency and were presented to blinded listeners for rating on a visual analog scale representing the gender spectrum, as well as word identification in a forced-choice task. We found a statistically significant association between the accuracy of word identification and the gender rating of utterances. However, there was no statistically significant difference in word identification accuracy for the formant-shifted conditions relative to an unshifted condition. Overall, these results support previous research in finding that word identification and speaker gender identification are interrelated processes; however, the findings also suggest that a small magnitude of shift in formant frequencies (of the type that might be pursued in a GAVT context) does not have a significant negative impact on the perceptual recoverability of isolated words.

Clinical Focus: The Development and Description of a Palette of Transmasculine Voices

PURPOSE

The study of gender and speech has historically excluded studies of transmasculine individuals. Consequently, generalizations about speech and gender are based on cisgender individuals. This lack of representation hinders clinical training and clinical service delivery, particularly by speech-language pathologists providing gender-affirming communication services. This letter describes a new corpus of the speech of American English-speaking transmasculine men, transmasculine nonbinary people, and cisgender men that is open and available to clinicians and researchers.

METHOD

Twenty masculine-presenting native English speakers from the Upper Midwestern United States (including cisgender men, transmasculine men, and transmasculine nonbinary people) were recorded, producing three sets of speech materials: Consensus Auditory-Perceptual Evaluation of Voice sentences, the Rainbow Passage, and a novel set of sentences developed for this project. Acoustic measures vowels (overall formant frequency scaling, vowel-space dispersion, fundamental frequency, breathiness), consonants (voice onset time of word-initial voiceless stops, spectral moments of word-initial /s/), and the entire sentence (rate of speech) that were made.

RESULTS

The acoustic measures reveal a wide range for all dependent measures and low correlations among the measures. Results show that many of the voices depart considerably from the norms for men's speech in published studies.

CONCLUSION

This new corpus can be used to illustrate different ways of sounding masculine by speech-language pathologists performing gender-affirming communication services and by higher education teachers as examples of diverse ways of sounding masculine.

Acoustic cues to femininity and masculinity in spontaneous speech

The perceived level of femininity and masculinity is a prominent property by which a speaker's voice is indexed, and a vocal expression incongruent with the speaker's gender identity can greatly contribute to gender dysphoria. Our understanding of the acoustic cues to the levels of masculinity and femininity perceived by listeners in voices is not well developed, and an increased understanding of them would benefit communication of therapy goals and evaluation in gender-affirming voice training. We developed a voice bank with 132 voices with a range of levels of femininity and masculinity expressed in the voice, as rated by 121 listeners in independent, individually randomized perceptual evaluations. Acoustic models were developed from measures identified as markers of femininity or masculinity in the literature using penalized regression and tenfold cross-validation procedures. The 223 most important acoustic cues explained 89% and 87% of the variance in the perceived level of femininity and masculinity in the evaluation set, respectively. The median fo was confirmed to provide the primary cue, but other acoustic properties must be considered in accurate models of femininity and masculinity perception. The developed models are proposed to afford communication and evaluation of gender-affirming voice training goals and improve voice synthesis efforts.

Auditory free classification of gender diverse speakersa)

Auditory attribution of speaker gender has historically been assumed to operate within a binary framework. The prevalence of gender diversity and its associated sociophonetic variability motivates an examination of how listeners perceptually represent these diverse voices. Utterances from 30 transgender (1 agender individual, 15 non-binary individuals, 7 transgender men, and 7 transgender women) and 30 cisgender (15 men and 15 women) speakers were used in an auditory free classification paradigm, in which cisgender listeners classified the speakers on perceived general similarity and gender identity. Multidimensional scaling of listeners' classifications revealed two-dimensional solutions as the best fit for general similarity classifications. The first dimension was interpreted as masculinity/femininity, where listeners organized speakers from high to low fundamental frequency and first formant frequency. The second was interpreted as gender prototypicality, where listeners separated speakers with fundamental frequency and first formant frequency at upper and lower extreme values from more intermediate values. Listeners' classifications for gender identity collapsed into a one-dimensional space interpreted as masculinity/femininity. Results suggest that listeners engage in fine-grained analysis of speaker gender that cannot be adequately captured by a gender dichotomy. Further, varying terminology used in instructions may bias listeners' gender judgements.

Speech beyond the binary: Some acoustic-phonetic and auditory-perceptual characteristics of non-binary speakers

Speech acoustics research typically assumes speakers are men or women with speech characteristics associated with these two gender categories. Less work has assessed acoustic-phonetic characteristics of non-binary speakers. This study examined acoustic-phonetic features across adult cisgender (15 men and 15 women) and subgroups of transgender (15 non-binary, 7 transgender men, and 7 transgender women) speakers and relations among these features and perceptual ratings of gender identity and masculinity/femininity. Differing acoustic-phonetic features were predictive of confidence in speaker gender and masculinity/femininity across cisgender and transgender speakers. Non-binary speakers were perceptually rated within an intermediate range of cisgender women and all other groups.

Intonation Parameters in Gender Diverse People

OBJECTIVES/HYPOTHESIS

Although intonation is often addressed in speech training for gender diverse individuals, the relationship between intonation and femininity/masculinity ratings remains unclear. The aim of this study was to examine differences in intonation parameters in gender diverse individuals. Moreover, the relationship between acoustic intonation parameters and femininity/masculinity ratings was investigated.

METHODS

Speech samples of semistructured speech were elicited from cisgender (cis) (107 ciswomen, 104 cis men), transgender (trans) (19 trans women, 10 trans men), and non-binary (n = 11) individuals using a prosody protocol. An objective acoustic analysis was performed to compare intonation parameters (upward/downward/flat intonation shift, general and final intonation shift, general fundamental frequency range, fundamental frequency variation index) between groups. In addition, a listening experiment was conducted, consisting of a cis and gender diverse listening panel (n = 41). The listeners were asked to rate the femininity/masculinity of speech samples (n = 57) using a visual analogue scale. Correlational analyses were used to examine the relationship between intonation parameters and femininity/masculinity ratings.

RESULTS

Similarity was found in the intonation parameters of participants with a similar gender identity. In non-binary speakers, no significant differences in acoustic intonation parameters were found between these speakers and the cisgender speakers. In addition, no significant correlations were found between the acoustic intonation parameters and the femininity/masculinity ratings in the groups with cis men, cis women, and non-binary participants. However, moderate to strong significant correlations were found between acoustic intonation parameters and femininity/masculinity ratings in the trans participants.

CONCLUSIONS

Intonation is a "speech marker" that distinguishes between groups with a different gender identity. No relationship was observed between intonation and femininity/masculinity ratings for cisgender and non-binary speakers. However, the significant relationship between these parameters for transgender participants (trans men and trans women) provides evidence for intonation exercises in gender affirming voice, speech, and communication training, and therefore contribute to evidence-based intonation training in transgender persons.